1. Field of the Invention
The invention is directed to a programmable integrated circuit, and more particularly, to an integrated circuit having a programmable front end.
2. Description of Related Art
Systems for conducting seismic exploration are well known in the art. On land, a plurality of transducers are deployed over a region and configured to receive reflections of an acoustic signal from different geophysical layers beneath the surface of the earth. In the ocean, arrays of transducers may be towed behind a boat in a spaced configuration in order to detect those reflections. In transition regions, between land and ocean, sensors may be positioned underwater at fixed locations. Different types of sensors may be utilized for the different environments in which they may be deployed.
When utilizing a seismic system, a strong acoustic signal is generated by, for example, setting off an explosion or by utilizing an acoustic signal generator having a relatively high power output. Reflections of the acoustic signals from the geophysical layers are then received at the seismic sensors deployed over a given area and the signals recorded, typically, for later analysis.
In some configurations, a seismic sensor is co-located with an analog to digital converter, such as a delta-sigma modulator, which converts an analog signal from the sensor into a digital signal for recording and processing. Seismic exploration has exacting requirements for seismic sensors and for the electronics which process the signals derived from those sensors. There is therefore a need to be able to test both the sensors and related equipment to ensure that both devices and the associated electronics are functioning properly.